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dmaengine: add a release for dma class devices and dependent infrastr…
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…ucture

Resolves:
WARNING: at drivers/base/core.c:122 device_release+0x4d/0x52()
Device 'dma0chan0' does not have a release() function, it is broken and must be fixed.

The dma_chan_dev object is introduced to gear-match sysfs kobject and
dmaengine channel lifetimes.  When a channel is removed access to the
sysfs entries return -ENODEV until the kobject can be released.

The bulk of the change is updates to existing code to handle the extra
layer of indirection between a dma_chan and its struct device.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Dan Williams committed Jan 6, 2009
1 parent 4fac7fa commit 41d5e59
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Showing 5 changed files with 157 additions and 75 deletions.
106 changes: 83 additions & 23 deletions drivers/dma/dmaengine.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -64,36 +64,75 @@ static long dmaengine_ref_count;

/* --- sysfs implementation --- */

/**
* dev_to_dma_chan - convert a device pointer to the its sysfs container object
* @dev - device node
*
* Must be called under dma_list_mutex
*/
static struct dma_chan *dev_to_dma_chan(struct device *dev)
{
struct dma_chan_dev *chan_dev;

chan_dev = container_of(dev, typeof(*chan_dev), device);
return chan_dev->chan;
}

static ssize_t show_memcpy_count(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dma_chan *chan = to_dma_chan(dev);
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;

for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->memcpy_count;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->memcpy_count;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);

return sprintf(buf, "%lu\n", count);
return err;
}

static ssize_t show_bytes_transferred(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct dma_chan *chan = to_dma_chan(dev);
struct dma_chan *chan;
unsigned long count = 0;
int i;
int err;

for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->bytes_transferred;
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan) {
for_each_possible_cpu(i)
count += per_cpu_ptr(chan->local, i)->bytes_transferred;
err = sprintf(buf, "%lu\n", count);
} else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);

return sprintf(buf, "%lu\n", count);
return err;
}

static ssize_t show_in_use(struct device *dev, struct device_attribute *attr, char *buf)
{
struct dma_chan *chan = to_dma_chan(dev);
struct dma_chan *chan;
int err;

return sprintf(buf, "%d\n", chan->client_count);
mutex_lock(&dma_list_mutex);
chan = dev_to_dma_chan(dev);
if (chan)
err = sprintf(buf, "%d\n", chan->client_count);
else
err = -ENODEV;
mutex_unlock(&dma_list_mutex);

return err;
}

static struct device_attribute dma_attrs[] = {
Expand All @@ -103,9 +142,18 @@ static struct device_attribute dma_attrs[] = {
__ATTR_NULL
};

static void chan_dev_release(struct device *dev)
{
struct dma_chan_dev *chan_dev;

chan_dev = container_of(dev, typeof(*chan_dev), device);
kfree(chan_dev);
}

static struct class dma_devclass = {
.name = "dma",
.dev_attrs = dma_attrs,
.dev_release = chan_dev_release,
};

/* --- client and device registration --- */
Expand Down Expand Up @@ -420,7 +468,7 @@ static struct dma_chan *private_candidate(dma_cap_mask_t *mask, struct dma_devic
list_for_each_entry(chan, &dev->channels, device_node) {
if (chan->client_count) {
pr_debug("%s: %s busy\n",
__func__, dev_name(&chan->dev));
__func__, dma_chan_name(chan));
continue;
}
ret = chan;
Expand Down Expand Up @@ -466,22 +514,22 @@ struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, v

if (err == -ENODEV) {
pr_debug("%s: %s module removed\n", __func__,
dev_name(&chan->dev));
dma_chan_name(chan));
list_del_rcu(&device->global_node);
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
dev_name(&chan->dev), err);
dma_chan_name(chan), err);
else
break;
} else
pr_debug("%s: %s filter said false\n",
__func__, dev_name(&chan->dev));
__func__, dma_chan_name(chan));
chan = NULL;
}
mutex_unlock(&dma_list_mutex);

pr_debug("%s: %s (%s)\n", __func__, chan ? "success" : "fail",
chan ? dev_name(&chan->dev) : NULL);
chan ? dma_chan_name(chan) : NULL);

return chan;
}
Expand Down Expand Up @@ -521,7 +569,7 @@ void dmaengine_get(void)
break;
} else if (err)
pr_err("dmaengine: failed to get %s: (%d)\n",
dev_name(&chan->dev), err);
dma_chan_name(chan), err);
}
}

Expand Down Expand Up @@ -601,14 +649,20 @@ int dma_async_device_register(struct dma_device *device)
chan->local = alloc_percpu(typeof(*chan->local));
if (chan->local == NULL)
continue;
chan->dev = kzalloc(sizeof(*chan->dev), GFP_KERNEL);
if (chan->dev == NULL) {
free_percpu(chan->local);
continue;
}

chan->chan_id = chancnt++;
chan->dev.class = &dma_devclass;
chan->dev.parent = device->dev;
dev_set_name(&chan->dev, "dma%dchan%d",
chan->dev->device.class = &dma_devclass;
chan->dev->device.parent = device->dev;
chan->dev->chan = chan;
dev_set_name(&chan->dev->device, "dma%dchan%d",
device->dev_id, chan->chan_id);

rc = device_register(&chan->dev);
rc = device_register(&chan->dev->device);
if (rc) {
free_percpu(chan->local);
chan->local = NULL;
Expand Down Expand Up @@ -645,7 +699,10 @@ int dma_async_device_register(struct dma_device *device)
list_for_each_entry(chan, &device->channels, device_node) {
if (chan->local == NULL)
continue;
device_unregister(&chan->dev);
mutex_lock(&dma_list_mutex);
chan->dev->chan = NULL;
mutex_unlock(&dma_list_mutex);
device_unregister(&chan->dev->device);
free_percpu(chan->local);
}
return rc;
Expand All @@ -672,7 +729,10 @@ void dma_async_device_unregister(struct dma_device *device)
WARN_ONCE(chan->client_count,
"%s called while %d clients hold a reference\n",
__func__, chan->client_count);
device_unregister(&chan->dev);
mutex_lock(&dma_list_mutex);
chan->dev->chan = NULL;
mutex_unlock(&dma_list_mutex);
device_unregister(&chan->dev->device);
}
}
EXPORT_SYMBOL(dma_async_device_unregister);
Expand Down Expand Up @@ -845,7 +905,7 @@ dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
return DMA_SUCCESS;

WARN_ONCE(tx->parent, "%s: speculatively walking dependency chain for"
" %s\n", __func__, dev_name(&tx->chan->dev));
" %s\n", __func__, dma_chan_name(tx->chan));

/* poll through the dependency chain, return when tx is complete */
do {
Expand Down
14 changes: 7 additions & 7 deletions drivers/dma/dmatest.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -80,7 +80,7 @@ static bool dmatest_match_channel(struct dma_chan *chan)
{
if (test_channel[0] == '\0')
return true;
return strcmp(dev_name(&chan->dev), test_channel) == 0;
return strcmp(dma_chan_name(chan), test_channel) == 0;
}

static bool dmatest_match_device(struct dma_device *device)
Expand Down Expand Up @@ -325,7 +325,7 @@ static int dmatest_add_channel(struct dma_chan *chan)

dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
if (!dtc) {
pr_warning("dmatest: No memory for %s\n", dev_name(&chan->dev));
pr_warning("dmatest: No memory for %s\n", dma_chan_name(chan));
return -ENOMEM;
}

Expand All @@ -336,16 +336,16 @@ static int dmatest_add_channel(struct dma_chan *chan)
thread = kzalloc(sizeof(struct dmatest_thread), GFP_KERNEL);
if (!thread) {
pr_warning("dmatest: No memory for %s-test%u\n",
dev_name(&chan->dev), i);
dma_chan_name(chan), i);
break;
}
thread->chan = dtc->chan;
smp_wmb();
thread->task = kthread_run(dmatest_func, thread, "%s-test%u",
dev_name(&chan->dev), i);
dma_chan_name(chan), i);
if (IS_ERR(thread->task)) {
pr_warning("dmatest: Failed to run thread %s-test%u\n",
dev_name(&chan->dev), i);
dma_chan_name(chan), i);
kfree(thread);
break;
}
Expand All @@ -355,7 +355,7 @@ static int dmatest_add_channel(struct dma_chan *chan)
list_add_tail(&thread->node, &dtc->threads);
}

pr_info("dmatest: Started %u threads using %s\n", i, dev_name(&chan->dev));
pr_info("dmatest: Started %u threads using %s\n", i, dma_chan_name(chan));

list_add_tail(&dtc->node, &dmatest_channels);
nr_channels++;
Expand Down Expand Up @@ -408,7 +408,7 @@ static void __exit dmatest_exit(void)
list_del(&dtc->node);
dmatest_cleanup_channel(dtc);
pr_debug("dmatest: dropped channel %s\n",
dev_name(&dtc->chan->dev));
dma_chan_name(dtc->chan));
dma_release_channel(dtc->chan);
}
}
Expand Down
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